1. Field of the Invention
The present invention relates to a phased lock loop used on an integrated circuit to provide precise frequency and phase tracking of two signals.
2. Description of the Prior Art
In many applications, such as generating signals for testing integrated circuits, it is desirable to generate timing signals which have a great deal of precision. For example, some applications require two signals to be offset from one another by a predictable amount less than a nano second. Traditional means of generating signals with such precision have been very difficult and solutions have been very expensive.
Typically this type of precision in signal generation has not been available in many inexpensive integrated circuit technologies such as CMOS. This is because the process by which these integrated circuits are manufactured has not allowed for sufficient control of process parameters or the limiting of sensitivity to environmental factors so as to allow timing to be predicted at the degree of certainty required for such applications.